Nanoparticles: Synthesis and Film Deposition Using a Simple and Fast Centrifuge Sedimentation Method

Gold nanoparticles were prepared by reduction of gold cations suspended in sodium bis(2-ethylhexyl)sulfosuccinate (AOT) water-in-hexane microemulsions with another AOT microemulsion containing a reducing agent NaCNBH3. The size of the Au nanoparticles can be controlled by the W values (water/surfactant ratio) of the microemulsions and by the nanoparticle protecting agent dodecanethiol. Oleic acid-capped PbS nanoparticles were prepared by a reaction of PbO with bis(trimethylsilyl)sulfide (TMS), oleic acid (OA) and octadecene (ODE). The sizes of PbS nanaoparticles can be controlled by the reaction temperature and the molar ratio of OA/PbO. Colloidal nanoparticles synthesized can be deposited uniformly on flat substrate surfaces employing a standard centrifuge method and common solvents. Different substrates were chosen for the deposition, which included rigid, flexible, conductive, and insulating materials. All the nanoparticles adhered firmly to the substrates, albeit with different strengths. The adhesion strength of the nanoparticle film also varied with the substrates used. This centrifuge deposition method is a very simple and efficient process that can be applied to a wide variety of substrates and different nanoparticles. It allows good coverage and thickness control of the nanoparticle films and layer by layer deposition of different nanaoparticles in a very simple manner.